Most people associate vitamin D, the sunshine vitamin, with strong bones. But studies in the past few years have linked this essential nutrient to a bonanza of additional benefits—from fighting cancer and diabetes to strengthening muscles. Physicians in New Zealand have now linked the vitamin to yet one more apparent advantage: improved lung function.

Peter N. Black is a University of Auckland internist with a research interest in chronic obstructive pulmonary disease (COPD)—a category including diseases most people know as emphysema and chronic bronchitis. Classic signs of COPD are holes in lung tissue where inflammatory enzymes have homed in to destroy diseased cells. Although COPD is common in cigarette smokers, not all smokers develop this disease.

Scientists know that enzymes called matrix metalloproteinases play a role in creating COPD's lung damage. Since laboratory studies had indicated vitamin D could inhibit production of these enzymes, Black wondered if people who got plenty of the vitamin through sun exposure or supplements might be protected from the disease. So, he and colleague Robert Scragg decided to mine data on vitamin status and lung function for 14,000 U.S. residents—a nationally representative sample—who had participated in the National Health and Nutrition Examination Survey (NHANES).

In the December Chest, the researchers report that getting ample vitamin D doesn't prevent COPD, but it does appear to help people with and without this lung disease to breathe easier and more deeply. Indeed, Black told Science News Online, "We were taken aback at how large the effect was." The study showed that people who never smoked but who were getting little vitamin D had 35 percent worse lung function than did former smokers who were getting adequate amounts of the vitamin. Current smokers, regardless of their vitamin D intake, had worse lung function than did either of these groups.

Blow hard
To measure lung function, NHANES researchers had men and women blow as much air as they could, as fast as they could, into a device. The tool gives two readings: how much air a person forces from his or her lungs in the first second after starting to blow, a parameter known as forced expiratory volume in 1 second (FEV1), and the total volume expelled, known as forced vital capacity (FVC).

The two measures are related, but in people with lung disease, one may fall more than the other. For instance, in people with asthma, FEV1 falls more than FVC. The opposite is true in people who have lung fibrosis, essentially the development of scar tissue.

For their study, Black and Scragg grouped the NHANES participants into five roughly equal-size groups on the basis of how much vitamin D was in their blood. The group with the lowest D had no more than 40.4 nanomoles of the vitamin per liter (nmol/l) of blood, whereas the group with the highest concentration had at least 85.7 nmol/l.

Recent studies have suggested that the optimal vitamin D blood concentration for most adults is at least 75 nmol/l and that elderly people might need at least 100 nmol/l (see Vitamin D: What's Enough?). In the NHANES analysis, fewer than 40 percent of people had D blood concentrations of at least 75 nmol/l.

Mona Calvo of the U.S. Food and Drug Administration has coauthored studies reviewing people's vitamin D status in North America. She defines vitamin D deficiency as less than 37.5 nmol/l, a value that especially people of color fail to achieve in the United States. Presumably, this reflects the fact that dark skin blocks absorption of much of the ultraviolet light that a person's body needs to make vitamin D (see Understanding Vitamin D Deficiency).

In the NHANES data, both FEV1 and FVC correlated with blood–vitamin D concentrations: people in successively higher-concentration groups more strongly expelled air from their lungs. For instance, the average difference between those in the top vitamin group and those in the bottom one was 126 milliliters of air in FEV1. In absolute terms, that value is small, considering that a healthy person will typically have an FEV1 of between 3 and 4 liters of air, depending on age and gender.

However, Black notes, the effect of vitamin D on lung function is larger than what other studies have attributed to eating diets rich in fruits and antioxidant vitamins or to most environmental factors other than smoking.

Vitamin D might even slow the reduction in lung function attributable to age or disease, Black notes. Beginning in late middle age, even healthy people begin losing about 20 to 30 ml in their FEV1 reading each year. In smokers with COPD, the drop in lung function can be 50 to 100 ml/year.

For people with COPD, Black argues, preserving almost 130 ml in breathing capacity "could prove quite meaningful"—extending by several years the period during which they could breathe comfortably, especially during exercise.

He cautions, however, that the new findings are only suggestive. To prove that vitamin D—and not some other related factor—is responsible for the lung benefits, researchers must conduct a large experiment in which half of the participants are administered vitamin supplements or given supervised sun exposures and half aren't, Black says. Until then, he adds, it's too early to advocate vitamin D supplements for the sake of people's lungs. On the other hand, he adds, there are many other reasons—bone health, for instance—for making sure to get plenty of the sunshine vitamin.

Indeed, people with too little vitamin D appear to be paying a toll in health status, according to a trio of researchers from Boston University School of Medicine, the University of California, San Diego, and the San Francisco–based Sunlight, Nutrition and Health Research Center. Their new analysis, reported in the November Photochemistry and Photobiology, looked at U.S. incidences of diseases that appear to be higher in people with low vitamin D–blood concentrations—from osteoporosis-linked fractures to certain cancers. Overall, the researchers calculate, as many as 50,000 people may die prematurely in the United States each year from diseases related to vitamin D deficiency, at an estimated cost to society of at least $40 billion. That's at least seven times as much as the annual U.S. cost of cataracts and skin cancers attributable to excess sun exposure.

References:

Black, P.N., and R. Scragg. 2005. Relationship between serum 25-hydroxyvitamin D and pulmonary function in the Third National Health and Nutrition Examination Survey. Chest 128(December):3792-3798. Abstract available at http://www.chestjournal.org/cg.....28/6/3792.

Grant, W.B., C.F. Garland, and M.F. Holick. 2005. Comparisons of estimated economic burdens due to insufficient solar ultraviolet irradiance and vitamin D and excess solar UV irradiance for the United States. Photochemistry and Photobiology 81(November):1276-1286. Abstract available at http://dx.doi.org/10.1562/2005-01-24-RA-424.

PHILADELPHIA -- Researchers at the University of Pennsylvania School of Medicine are harnessing two new, non-invasive techniques to look more closely inside the working lungs - leading to early detection of diseases, like emphysema, before it becomes evident in other modes of imaging.

Mountain View, CA, October 9, 2007 - Broncus Technologies, Inc., a medical device company investigating the airway bypass procedure for the treatment of emphysema, today announced that the results of its open-label Exhale® Drug-Eluting Stent feasibility study have been published in the October issue of the Journal of Thoracic and Cardiovascular Surgery. Positive results include a statistically significant reduction in the amount of air trapped in the lungs and an improvement in breathing for patients at six months after the airway bypass procedure.

Airway bypass is a catheter-based bronchoscopic procedure designed to reduce lung hyperinflation and improve breathlessness (the clinical hallmarks of emphysema/COPD) by making new pathways for trapped air to exit the lungs. During the minimally invasive procedure, new openings are created in the airway wall connecting the damaged lung tissue to the natural airway. These pathways are supported and kept open by Exhale Drug-Eluting Stents. The hope is to improve quality of life by relieving severe symptoms including shortness of breath and hyperinflation of the chest.

Emphysema, a component of COPD, is a chronic, progressive, and irreversible lung disease characterized by the destruction of lung tissue. The loss of the lungs' natural elasticity and the collapse of airways in the lung combine to make exhalation ineffective, leaving emphysema sufferers with hyperinflation because they are unable to get air out of their lungs. Breathing becomes inefficient and patients have to work very hard just to breathe – making normal activities, like walking, eating or even bathing, difficult. Treatment options for most patients with emphysema are currently limited and generally result in anguished patients and frustrated physicians.

The prospectively-defined primary endpoint of this feasibility study was a reduction in residual volume (RV, the amount of air remaining in the lungs after full exhalation) at 6 months. The goal was for a 300mL reduction in RV. Overall the trial surpassed that goal with a 400mL improvement in RV over baseline at 6 months (p=0.04). Patients also showed a statistically significant improvement in the modified Medical Research Council Dyspnea Scale (mMRC), a breathlessness test, of -0.5 points (p= 0.025). Retrospective analysis revealed that patients with the most severe hyperinflation of their lungs (as determined by a residual volume to total lung capacity ratio above the median) derived the greatest benefit from airway bypass. At 6 months after the procedure, these patients showed a mean improvement in RV of 870mL (p=0.022).

“The management of emphysema poses a difficult challenge for the medical community as the disease progressively deprives patients of their ability to perform daily activities. These findings are encouraging because there are so few options for the millions patients who suffer from this disease,” states Paulo F.G. Cardoso, M.D., Ph.D, Division of Thoracic Surgery, Santa Casa de Porto Alegre-Pavilhao Pereira Filho Hospital, Brazil and lead author of the paper. “These results reveal significant improvements in pulmonary function and reduction in breathing difficulties out to six months and indicate that airway bypass is a potentially viable therapeutic option for patients with marked severe pulmonary destruction, whose only current option may be to wait for a lung transplant.”

“The data from this study are very exciting, as they help build the case that airway bypass might reduce hyperinflation and have long-term benefit,” states Cary Cole, CEO of Broncus. “We hope to continue this success with the current, pivotal EASE Trial, our largest clinical study to date.”

New research shows that antioxidants—vitamins A, C, and E—may help improve lung function in people who smoke. Researchers from Bangladesh compared the lung function of 200 healthy male smokers who took one vitamin—A, C, or E— or all three in combination for 2 months. Results showed that patients taking vitamins, improved their lung function after 2 months, with those taking all three vitamins in combination experiencing the largest improvement in lung function. The study also found that when vitamin supplementation was ceased, smokers’ lung function decreased, leading researchers to conclude that the beneficial effects of vitamins are temporary if they are not taken consistently.

Researchers from Manhasset High School in New York, say a student athlete’s respiratory muscles can be trained and strengthened through athletic activity. The spirometric values of both student athletes (swimmers and wrestlers) and non-athletes were analyzed and the differences between the two were calculated. Researchers found that athletes had significantly better lung function when compared to the non-athletes. They also found that among the athletes, wrestlers were shown to have better lung function than swimmers.

ALCOHOL MAY BE GOOD FOR LUNG FUNCTION
(Wednesday, October 24, 1:30 PM EST)

People who are light to moderate drinkers may experience better lung function than abstainers, according to a study from Kaiser Permanente Medical Center. Researchers examined data from health care exams administered to more than 177,000 members of a health plan from 1964-1973. Included were lung function data and questionnaire items regarding alcohol habits. Results showed that independent of smoking and evidence of lung or heart disease, light to moderate drinkers were less likely to have abnormal lung function.

A new study says spirometry testing is underutilized in outpatient medical clinics. The lung function test is recommended for proper diagnosis of COPD. Researchers from the University or Connecticut and St. Francis Hospital analyzed data for patients who were aged 45 or older, and were either diagnosed with COPD or asthma, a current smoker, or experiencing respiratory symptoms. Results showed that only one-third of patients received spirometry. Less than half of those diagnosed with COPD had spirometry confirmation.

A new study reveals that patients with COPD commonly receive the same medication prescriptions, regardless of whether or not they’ve undergone spirometry testing. Over a 1-year period, researchers from Illinois collected data from more than 100,000 veterans with COPD. While only one-quarter of those included underwent spirometry, the test did not affect the type or amount of medications prescribed.